Conventionally, there is disclosed a non-contact voltage measurement device which measures an alternating voltage (measurement target voltage) flowing in conductive wires in insulated and coated wires without contacting the conductive wires. Patent Documents 1 to 3 disclose examples of such a non-contact voltage measurement device.
Generally, a non-contact voltage measurement device includes a probe and an electric circuit. When placing the probe close to the wire to produce a coupling capacitance between the probe and the wire, the non-contact voltage measurement device measures a measurement target voltage, based on a voltage signal input to the electric circuit via the probe.
However, there is a case where, in a non-contact voltage measurement device, when an electric circuit and a voltage source other than wires are capacitively coupled, noise is superimposed on a voltage signal of the electric circuit in some cases. The noise superimposed on the voltage signal causes a decrease in measurement precision of measurement target voltage. Hence, it is considered to arrange around an electric circuit an electric field shield for blocking an external electric field.